MI3 Peat production

Development

Altogether some 110 000 hectares of mires have been used for peat production in Finland. This equals approximately 1.2% of the present total mire area. The area under active peat production is 80 000 hectares while the remaining 30 000 hectares consist of areas where production has recently ceased. Most of the peat production occurs in coastal Ostrobothnia: nearly 70% of the production areas are situated in the provinces of Oulu and Western Finland. The effects of peat production on biodiversity are most pronounced within the delivery areas of the largest peat energy plants.

Impact on biodiversity

In the areas directly affected, peat production equals a complete destruction of the original mire fauna and flora. At the beginning of production all vegetation is removed and the area remains barren throughout the active extraction phase. After the production has ceased, vegetation begins to return, but since the exposed peat layer contains no seed bank the restoration process is normally quite slow. In time complex species communities will develop into abandoned extraction areas, but their species compositions remain different from the pre-extraction state.

As a result of peat production the area of pristine mires has declined. Especially some scarce mire types have suffered from the practice. These include... Peat production affects also areas surrouding the actual production sites. The large-scale draining of production areas alters the hydrology of nearby mires and the heavy machinery required for production creates noise pollution in often otherwise silent areas.

An indirect effect of peat production on biodiversity is caused by the leaching of nutrients and organic matter from production areas. The extensive drainage and harvesting of the peat layer causes loading of suspended solids, dissolved organic matter, nitrogen and phosphorus into natural water bodies below production areas. These result in siltation, eutrofication and other changes which decrease the ecological status of these waters. Peat production areas are often situated in headwater areas with few lakes, a fact which makes the watercouses affected especially vulnerable to eurtophication.

Increases in the density and decreases in diversity of benthic fauna have been observed in streams below production areas. In spite of the overall increase of productivity, salmonid fishes feeding on benthic fauna seem to grow slower these steams. The mortality of incubated Brown Trout roe has also been found to be higher in affected steams. This is most likely caused by increased siltation.

The environmental impacts of loading have been decreased by using several pollution control methods which have been developed especially for peat production. An Environmental Impact Assessment is required whenever a new site of over 150 hectares in area is planned for production. Efforts have also been made since mid 1990's to map out the biodiversity values of potential extraction areas in order to refrain from production on the most valuable ones. The total effect of peat production on biodiversity depends also on the after use of production areas. Some areas may be restored back into mire habitats, but this has been a minority practice within the past decade.